Mars Global Surveyor
Mars Orbiter Camera

"Cottage Cheese" Texture on the Martian North Polar Cap in Summer

MGS MOC Release No. MOC2-213, 8 March 2000

This image is illuminated by sunlight from the upper left.

Martian Dairy Products?
If parts of the south polar cap can look like swiss cheese
(see "Martian 'Swiss Cheese'"), then parts
of the north polar cap might as well look like some kind of
cheese, too. This picture
shows a cottage cheese-like texture on the surface of a part
of the residual--summertime--north polar cap.

The north polar cap surface is mostly covered by pits, cracks,
small bumps and knobs. In this image, the cap surface appears bright
and the floors of pits look dark.
Based upon observations made by the Mariner 9 and Viking orbiters
in the 1970s, the north polar residual cap is thought to contain mostly
water ice because its summertime temperature is usually near the freezing
point of water and water vapor was observed by the Vikings to be
coming off the cap
during summer. The south residual cap is different---its temperatures
in summer remain cold enough to freeze carbon dioxide, and very little to
no water vapor has been observed to come off the south cap in summer.

The pits that have developed on the
north polar cap surface are closely-spaced relative to the
very different depressions
in the south polar cap. The pits are estimated from the length of
shadows cast in them to be less than about 2 meters (5.5 feet) deep.
These pits probably develop slowly over thousands of years of
successive spring and summer seasons.

This picture was taken by the Mars Global Surveyor (MGS)
Mars Orbiter Camera (MOC) during northern summer on April 5, 1999. The
picture is located near 82.1°N, 329.6°W and covers an area
1.5 km wide by 3 km long (0.9 x 1.8 miles) at a resolution of 3 meters
(10 ft) per pixel.

Image credit: NASA/JPL/Malin Space Science Systems

Malin Space Science Systems and the California Institute of Technology
built the MOC using spare hardware from the Mars Observer mission. MSSS
operates the camera from its facilities in San Diego, CA. The Jet Propulsion
Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor
spacecraft with its industrial partner, Lockheed Martin Astronautics, from
facilities in Pasadena, CA and Denver, CO.